UH Hilo researchers design sustainable wastewater systems

By University of Hawaiʻi at Hilo | October 20, 2017

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Researchers at the University of Hawaiʻi at Hilo are committed to the environment and are doing their part to help HawaiʻiIsland industries utilize more renewable and sustainable energy sources. Research into sustainable energy is an ever-growing field with plenty of space for innovation.

Shihwu Sung, professor of applied engineering at UH Hilo, is currently conducting research on converting waste into biodiesel energy.

“I’ve always been very interested in the environment,” Sung says. “Through my research I want to focus on decreasing the amount of fossil fuels used, and increasing the amount of renewable energies on Hawaiʻi Island.”

Sung’s research is currently being conducted in the Renewable Energy Lab on the UH Hilo campus, where he has built a lab scale of an upflow anaerobic sludge blanket (UASB) reactor, a single tank wastewater treatment system.

The project is funded by and in conjunction with Big Island Biodiesel, a Keaʻau based plant committed to “a sustainable, community-based vision.”

The research

“This UASB reactor machine starts with wastewater, undergoes processes of conversion, and ultimately produces a biogas that contains methane,” Sung explains. “The produced biogas can then be used as a primary source of energy.”

The wastewater that goes into the reactor is an organic product, containing natural carbons. The carbons break down through the use of anaerobic organisms, which, through a continuous upward flow, creates biogas.

“The lab scale UASB reactor was created to test the method on a smaller scale and determine if this process is compatible for the Big Island,” says Sung. “We also have a pilot scale at the biodiesel plant, and eventually, we will have a full scale UASB reactor.”

Chayanon Sawatdeenarunat, who received his PhD in molecular biosciences and bioengineering from UH Mānoa, is now a postdoctoral researcher on this project.

Sawatdeenarunat emphasizes the universality of waste conversion technologies. “It can be used in practically any industry, any company that uses a lot of energy can make use of this technology and turn their waste into fuel, becoming more sustainable,” he says.

Sawatdeenarunat continues, “This is the first waste to energy conversion process being researched on the Big Island. It is good for the island, and we are able to continue our research because the people of Hawai‘i have their own environmental concerns.”

The pilot scale model of the UASB reactor is located in Keaʻau at Big Island Biodiesel, a branch of Pacific Biodiesel, a company that converts used cooking oil and grease into biodiesel fuel. If the pilot scale reactor proves to work in its intended environment, the full scale model will allow the plant to convert its waste products into biogas, which will supplement the energy needs of the plant.

Sung believes that Hawaiʻi Island is a prime location for this type of research. “We need biofuel here, because, well, the energy practices are not very good right now,” he says. “Creating more sources of renewable energy and technologies of waste conversion will help Hawaiʻi become more independent. Everyone should believe in this idea.”

Read UH Hilo Stories for more about the project and how Sung and Sawatdeenarunat are also helping Hawaiʻi Island coffee mills become more sustainable.